“He acknowledged that the police had been behind him when he was driving the car. He maintained that the brakes had failed.

“He started crying again and continually said he was sorry.

“Road traffic collision investigators examined the vehicle and found no defects which would have caused or contributed to the collision.”

The story emerged on Monday after Jenkin, a prisoner of YOI Polmont in Stirlingshire, pleaded guilty to causing Ms Pirrie’s death by driving dangerously and other traffic offences before judge Lord McEwan.

The judge had been told that Ms Pirrie’s family were grieving over the loss of their loved one.

He wept loudly as Mr Prentice told the court about the circumstances surrounding the incident. Jenkin’s solicitor got up from her seat in the court to hand her weeping client a hanky.

Mr Prentice told the court: “She was a much loved mother, daughter and partner who leaves behind her five-year-old son Matthew, who is now in the full time custody of his father.”

Mr Prentice told the court that Jenkin and a friend had bought the car for £40 from a man who advertised it on Gumtree, an Internet sales site.

During the afternoon of May 12 2016, Jenkin drove the car around Edinburgh with a number of passengers.

Around 7.45pm that night, two police officers saw Jenkin driving the car in the city’s Milton Road.

Mr Prentice said the Ka was “in a state of disrepair” and officers checked the Police National Computer because they were suspicious about the vehicle.

After discovering that the vehicle wasn’t insured and that the DVLA had been notified that it was off road, the coppers asked for assistance.

A BMW traffic police car then responded and requested Jenkin to stop the car on the A7 road close to a “Park and Ride” facility.

Mr Prentice said: “The accused failed to stop the vehicle and accelerated away from the police.

“The police officers informed the control room that the vehicle had failed to stop and was now being pursued.

“The accused continued to accelerate northwards on the A7. He continued at a grossly excessive speed towards Danderhall at the junction with Newton Church Road and passed a witness standing at a bus stop.

“She remarked on the high speed of the Ford Ka which continued travelling towards Old Dalkeith Road.

“Another witness was travelling southwards on Old Dalkeith Road having passed the Royal Infirmary of Edinburgh when he observed the silver Ford Ka being driven towards him on the other side of the road.

“He considered that the car was travelling at a grossly excessive speed when he saw the vehicle heading towards the Royal Infirmary of Edinburgh then overtaking other vehicles before he lost sight of it.

“A witness who was walking her dogs on Old Dalkeith Road, at Little France Road, heard the loud sound of a car engine and saw the silver Ford Ka travelling towards her. She took evasive action by running back to the pavement.

“The deceased Jill Pirrie was returning home from the Royal Infirmary having completed her shift that day. She normally walks to her home which was just over a mile away.

“The accused drove the Ford Ka on Old Dalkeith Road dangerously by driving at a grossly excessive speed. He attempted to turn left onto Kingston Avenue. However, he failed to negotiate the turn and lost control of the vehicle. The car skidded across the junction.

“The car then struck Jill Pirrie from behind throwing her against the wall on the north side of the pavement and colliding with a roadside signpost and the wall there before coming to rest.

“Jill Pirrie was thrown to the left side of the car and fell onto the north pavement where she lay seriously injured. The pedestrian witnesses went to her aid.”

Mr Prentice told the court that Jenkin and a passenger left the vehicle at that point and ran away. Meanwhile, paramedics arrived and detected Ms Pirrie was in cardiac arrest and she had injuries to the right side of her chest, right leg and pelvic area.

Mr Prentice added: “Ms Pirrie was conveyed to the Royal Infirmary of Edinburgh where urgent treatment was given by medical staff. Despite the best endeavours of the medical staff it became clear that the resuscitation attempts were in vain. At 21:21 hours, the treatment of the deceased was stopped and life was pronounced extinct.”

Police discovered that Jenkin was the driver of the car and had made several attempts to find him. But on 5pm on May 13 2016, Jenkin turned up at the hospital for treatment in the company of his solicitor. He later confessed to police whilst receiving treatment from Ms Pirrie’s colleagues for a cracked rib and bruising.

Defence advocate Brian McConnachie QC told the court that he would reserve his plea of mitigation until the sentencing hearing.

Lord McEwan deferred sentence for the court to obtain reports.

Jenkin will be sentenced at the High Court in Glasgow on August 7 2016.